Underwater structure

ABSTRACT

An underwater structure comprising a buoyant housing immersed in a body of water and an anchoring system connected between the housing and the floor of the body of water and cooperating with the fluid pressure of the water to maintain the housing in a stable position a predetermined distance above the floor. The housing is an inverted, generally cup-shaped structure having an open bottom portion, and the anchoring system comprises a plurality of tiedown legs having their upper ends attached to the housing and their upper ends attached to the housing and their lower ends anchored to the floor of the body of water in which the housing is immersed. The tiedown legs are preferably hollow tubular members sealed to prevent water from entering the interior thereof, and of such dimensions as to be relatively weightless in water and of neither negative nor positive buoyancy. The lower ends of the tiedown legs are anchored to the floor of the body of water in which the housing is immersed by means of rods which extend into cavities in the floor and are bonded thereto by grout. An exemplary use of the underwater structure of this invention, an aquadome, is for housing drilling equipment and/or personnel for recovery of petroleum and natural gas from offshore oil fields.

United States Patent Ernest A. Clara Los Angeles County, Calif. (GMG Associates 12150 Stagg St. North Hollywood, Calif. 91605) [72] Inventor,

[21] AppLNo. 801,341 [22] Filed Feb. 24, 1969 [45] Patented Mar. 23, 1971 [54] UNDERWATER STRUCTURE 14 Claims, 7 Drawing Figs.

[52] U.S.Cl 61/46,9/8 [51] Int. Cl. ..B63b 35/44, B63b21/00 [50] FieldofSearch 6l/46,46.5, 69,723; 166/.5; 114/.5 (D), l6;9/8

[5 6] References Cited UNITED STATES PATENTS 2,775,095 12/1956 Harris 61/46 2,777,669 1/1957 WillisetaL. 114/.5X 3,255,591 6/1966 Thornley.... .6l/46 3,472,032 10/1969 Howard 61/46 Primary Examiner-J. Karl Bell ABSTRACT: An underwater structure comprising a buoyant housing immersed in a body of water and an anchoring system connected between the housing and the floor of the body of water and cooperating with the fluid pressure of the water to maintain the housing in a stable position a predetermined distance above the floor. The housing is an inverted, generally cup-shaped structure having an open bottom portion, and the anchoring system comprises a plurality of tiedown legs having their upper ends attached to the housing and their lower ends anchored to the floor of the body of water in which the housing is immersed. The tiedown legs are preferably hollow tubular members sealed to prevent water from entering the interior thereof, and of such dimensions as to be relatively weightless in water and of neither negative nor positive buoyancy. The lower ends of the tiedown legs are anchored to the floor of the body of water in which the housing is immersed by means of rods which extend into cavities in the floor and are bonded thereto by grout. An exemplary use of the underwater structure of this invention, an aquadome, is for housing drilling equipment and/or personnel for recovery of petroleum and natural gas from offshore oil fields.

UNDERWATER STRUCTURE BACKGROUND OF THE INVENTION The present invention relates to an improved underwater st structure, an aquadome, which is particularly useful as a station for drilling oil wells beneath bodies of water, regardless of weather conditions.

underwater structure of this invention employed as a support In recent years, numerous types of drilling stations have been designed for drilling oil wells in offshore locations. These stations have included platforms supported on pilings which extend to the ocean floor, platforms supported on pontoons, platforms supported on hydraulic legs which are operable to lift the platform above the-water surface; and underwater drilling chambers adapted tov rest on and be anchored to the ocean floor. V

Those platforms supported Ion pilings, pontoons and hydraulic legs are constantly exposed to .wind, wave, action and other weather conditions. so that drilling operations therefrom must be restricted during storms. The underwater drilling chambers adapted to rest on the ocean floor are relatively expensive to construct and maintain, and are not readily accessible to men and material during drilling operations since the chambers are sealed from the water pressure. Moreover, such closed drilling chambers require relatively elaborate sealing devices around the portion 'of the drilling pipe which passes through the chamber wall.

SUMMARY OFTHEINVENTION proved underwater structure which-may be employed for a variety of purposes.

It is a further object of this. invention to provide animproved underwater structure which may be used, for example,

as a drillingstation which is not exposed to weather conditions, is relatively inexpensive to construct and operate, andis relatively accessible to supply craft.

It is a further object of this invention to provide improved anchoring means for,anchoring a buoyantobject to the floor. of a body of water. r I

The foregoingand otherobjects and advantages have been realized by the structure of the present invention which comprises a housing adapted to be inimersedin a body of water, and tiedown means formaintaining the housing in a stable position a predetermined distance above the floor of the body of water in which itis immersed. The housing has an open bottom portion for exposing the interior thereof to the pressure of the water in which the housingfis immersed, and a fluid of lower specific gravity than the water-in which the housing is immersed fills the housing and prevents the water from rising above a predetermined level therein. The tiedown means are preferably rigid tubular legs sealed from the water and of such dimensions as to be relatively weightless in water and of neither negative nor positive buoyancy. The lower ends of the tiedown legs are anchored to the floor by means of rods which extend into cavities in the floor and'are bonded thereto by grout.

The underwater structure of this invention, an aquadome, is particularly useful inrec'overing offshore petroleum andnatural gas, and when so used the housing may contain or support drilling equipment and/or storage chambers.

BRIEF DESCRIPTION OF THE DRAWINGS derwater fluid storage chamber.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1-4 of the drawings show the improved underwater structure of the present invention, an aquadome, embodied in an underwater drilling station. The station comprises a houslng I0 having an at least partially open bottom portion 12 (FIG. 4) submerged in the ocean l4 and secured to the ocean floor 16 by a plurality of rigid tubular tiedown legs 18.

As best shown. in FIGS. 3 and 4, the housing 10 comprises upper section 20 having living'and storage quarters 22, and a lower section 24 which houses a drilling platform 26 and various drilling equipment. The drilling equipment may include a rotary table 28, drive means 30 and draw works 32 therefor (shown in block iiiagram form), mud pumps, air compressors, electrical generating equipment, drilling mud storage chambers, gas separators, an atmosphere conditioning and filtration system, and a diesel electric power plant (not shown). Below the drilling platform 26 are storage chambers 34 for fuel,

.The' column 43 may function, for example, as a combination .air intake-exhaust pipe, and/or as an equipment and personnel access hatch.

The open bottom portion of the housing 10 permits a plurality of wells to be drilled from a single housing using a plurality of riser pipes 44 (-FIG. 1

As best shown in FIGS. 1 and 2, the housing 10 is anchored to the ocean floorl6 by a series of tubular legs 18 which extend between'various fittings on the housing to anchoring -devices 45 on the ocean floor I6. The tubular legs 18 have derwater structure of the present invention, an aquadome,

embodied in an underwater drilling station submerged in the ocean and anchored a predetermined distance above the,

ocean floor, and a portion of a supply craft delivering supplies to the station; f r t FIG. 2 is a plan view along the line 2-2 of FIG. I; I

F IG. 3 is a sectional plan view of the station taken along the line 3-3 ofFIG. l; r

of the station shown in-FIG. 1 taken relatively thin walls, as shown at 46 in FIG. 4, and are sealed to prevent water from entering the interior thereof. The size and weight of the tiedown legs 18 are such that the legs are relatively weightless in water, and of neither negative nor positive buoyancy.

Asbest shown in FIG. I the bottoms of the tubular tiedown legs 18 are anchored to; the ocean floor 16 by anchoring means 48. The anchorin g means may comprise a truss 50 attached to a plurality of downwardly extending rods 52 (preferably made of steel) embedded in concrete grout 54 in cavities in the ocean floor. Alternatively, as shown in FIGS. 5- -7, the bottom of each tiedown leg 18 may be anchored to the ocean floor by means of a single rod 52.

In use, the upward force on the buoyant housing 10 created by the pressure of the ocean water places the tubular tiedown legs 18 intension. Thus, the tiedown legs and the pressure of the ocean water cooperateto maintain the housing in a stable position a predetermined distance above the ocean floor. The air or other fluid in the housing is of lower specific gravity than the ocean water and of sufficient pressure relative to the pressure of the ocean water to prevent the water. from rising above a predetermined level within the housing.

The use of the closed tubular tiedown legs 18 in place of conventional cables to anchor the housing 10 to the ocean floor 16 is particularly advantageous. Cables stretch and sag permitting the stations or platforms which they anchor to rotate and move in the water. The tubular tiedown legs 18 do not stretch, except for negligible elongation due to tension stress, and thus will not permit significant movement of the housing 10.

While the present invention has been described above and illustrated in FIGS. 1-4 with reference to an underwater drilling station, it is contemplated that this invention may be employed to advantage in a variety of other embodiments.

For example, as shown in FIG. 5, an open-bottom housing 70 constructed in accordance with the teachings of the present invention may be employed to support an external drilling platform 62 above the surface of the ocean 14. An internal fluid 64 in the housing prevents the ocean water from rising above a predetermined level in the housing. The fluid 64 is of lower specific gravity than the ocean water and of sufficient pressure to prevent the ocean water from rising above the predetermined level in the housing. A risen pipe 66 extends from the drilling platform 62 and through a passage 68 in the housing 60 to the ocean floor 16.

As shown in FIG. 6, an open-bottom housing 70constructed according to the teachings of this invention may be employed to support an external station 72 (e.g. a weather station) above the surface of the ocean 14. Ocean water is prevented from rising above a predetermined level within the housing 70 by means of the pressure of an internal fluid 74 which is of lower specific gravity than the ocean water.

As shown in FIG. 7, a housing 80 constructed according to the teachings of the present invention may be employed as a storage chamber for fluid 82 or equipment or facilities (not shown). The pressure of the internal fluid 82 which is of lower specific gravity than the ocean water, prevents the water from rising above a predetermined level within the housing 80.

It is contemplated that the teachings of the present invention may be employed for a variety of purposes other than those described above and shown in the drawings. For example, it is contemplated that underwater structures constructed in accordance with the teachings of this invention may be employed for storing oil, fuel or gas; for refueling ocean vessels; for housing habitation underwater; for harvesting or processing sea life; for communications stations; for submarine docking stations; for housing power production plants; for undersea mining; for tunnels between land masses; for various military uses; and for numerous other purposes.

lclaim:

1. An underwater structure, comprising:

a housing immersed in a body of water;

means in the housing for exposing the interior thereof to the pressure ofthe water in which said housing is immersed;

a fluid at least partially filling the interior of said housing;

said fluid being of lower specific gravity than the water in which said housing is immersed, and said fluid being of such pressure relative to the pressure of the water in which said housing is immersed as to prevent the water from rising above a predetermined level within the housing; and

tiedown means connected to and extending between said housing and the floor of the body of water in which said housing is immersed for anchoring the housing to the floor and maintaining the housing a predetermined distance above the floor.

2. An underwater structure according to claim 1, wherein said housing comprises an inverted, generally cup-shaped structure having a substantially open bottom portion.

3. An underwater structure according to claim 2, and further comprising drilling equipment mounted within said housing; said drilling equipment including a pipe extending downwardly through the open bottom portion of the housing.

4. An underwater structure according to claim 1, and further comprising a platform mounted on said housing and spaced above said housing to extend above the surface of the body of water in which the housing is immersed.

5. A structure according to claim 4, wherein said platform comprises a drilling platform; and further comprising means defining a passage extending through said housing, and riser and drill pipes extending downwardly from said drilling platform and through said passage in said housing.

6. An underwater structure according to claim 1, and further comprising an access column having a lower end communicating with the interior of said housing and extending up wardly and terminating in an upper end extending above the surface of the body of water in which said housing is immersed.

7. An underwater structure according to claim I, wherein said tiedown means comprises a relatively rigid tubular member having an upper end connected to said housing and a lower end anchored to the floor of the body of water in which said housing is immersed, wherein said tubular tiedown member is a hollow tubular member sealed to prevent water from entering the interior thereof and of such dimensions as to be relatively weightless in water and of neither negative not positive buoyancy.

8. An underwater structure according to claim 7, and further comprising anchoring means for securing the lower end of the tubular tiedown member to the floor of the body of water in which said housing is immersed; said anchoring means comprising a truss having a plurality of downwardly extending anchoring rods connected thereto; said anchoring rods extending into cavities in the floor of the body of water in which said housing is immersed.

9. An underwater structure according to claim 8, and further comprising grout surrounding the anchoring rods and bonding them to the floor of the body of water in which said housing is immersed.

10. An underwater structure according to claim I, wherein said tiedown means comprises a plurality of relatively rigid tubular members having their upper ends connected to said housing at spaced locations thereon and lower ends anchored to the floor of the body of water in which said housing is immersed and wherein said tubular members are of such dimensions as to be essentially weightless in water and of neither negative nor positive buoyancy.

11. In combination, a buoyant object and tiedown means for anchoring said buoyant object to the floor of a body of water; said tiedown means comprising a relatively rigid, hollow tubular member sealed to prevent water from entering the interior thereof and of such dimensions as to be relatively weightless in water and of neither negative nor positive buoyancy; said tubular tiedown member having an upper end connected to said buoyant object and a lower end adapted to be anchored to the floor of the body of water.

12. An underwater structure, comprising:

a housing adapted to be immersed in a body of water;

means in the housing for exposing the interior thereof to the pressure of the water in which said housing is to be immersed; said housing being adapted to contain a fluid at least partially filling the interior thereof; said fluid being of lower specific gravity than the water in which said housing is to be immersed, and said fluid being of such pressure relative to the pressure of the water in which said housing is to be immersed as to prevent the water from rising above a predetermined level within the housing; and

tiedown means connected to said housing and adapted to extend between said housing and the floor of the body of water in which said housing is to be immersed for anchoring the housing to the floor and maintaining the housing a predetermined distance above the floor.

13. An underwater structure according to claim 12, and further comprising an access column having a lower end communicating with the interior of said housing and extending upwardly and terminating in an upper end spaced substantially above said housing, whereby said upper end of said access column will extend above the surface ofa body of water when said housing is immersed in that body of water.

member having an upper end connected to said housing and a lower end adapted to be anchored to the floor of a body of water in which said housing is immersed and wherein said tuneither negative n'or positive buoyancy.

bular tiedown member is a hollow tubular member sealed to prevent water from entering the interior thereof and of 'such dimensions as to be relatively we'ghtless in water and of 

1. An underwater structure, comprising: a housing immersed in a body of water; means in the housing for exposing the interior thereof to the pressure of the water in which said housing is immersed; a fluid at least partially filling the interior of said housing; said fluid being of lower specific gravity than the water in which said housing is immersed, and said fluid being of such pressure relative to the pressure of the water in which said housing is immersed as to prevent the water from rising above a predetermined level within the housing; and tiedown means connected to and extending between said housing and the floor of the body of water in which said housing is immersed for anchoring the housing to the floor and maintaining the housing a predetermined distance above the floor.
 2. An underwater structure according to claim 1, wherein said housing comprises an inverted, generally cup-shaped structure having a substantially open bottom portion.
 3. An underwater structure according to claim 2, and further comprising drilling equipment mounted within said housing; said drilling equipment including a pipe extending downwardly through the open bottom portion of the housing.
 4. An underwater structure according to claim 1, and further comprising a platform mounted on said housing and spaced above said housing to extend above the surface of the body of water in which the housing is immersed.
 5. A structure according to claim 4, wherein said platform comprises a drilling platform; and further comprising means defining a passage extending through said housing, and riser and drill pipes extending downwardly from said drilling platform and through said passage in said housing.
 6. An underwater structure according to claim 1, and further comprising an access column having a lower end communicating with the interior of said housing and extending upwardly and terminating in an upper end extending above the surface of the body of water in which said housing is immersed.
 7. An underwater structure according to claim 1, wherein said tiedown means comprises a relatively rigid tubular member having an upper end connected to said housing and a lower end anchored to the floor of the body of water in which said housing is immersed, wherein said tubular tiedown member is a hollow tubular member sealed to prevent water from entering the interior thereof and of such dimensions as to be relatively weightless in water and of neither negative nor positive buoyancy.
 8. An underwater structure according to claim 7, and further comprising anchoring means for securing the lower end of the tubular tiedown member to the floor of the body of water in which said housing is immersed; said anchoring means comprising a truss having a plurality of downwardly extending anchoring rods connected thereto; said anchoring rods extending into cavities in the floor of the body of water in which said housing is immersed.
 9. An underwater structure according to claim 8, and further comprising grout surrounding the anchoring rods and bonding them to the floor of the body of water in which said housing is immersed.
 10. An underwater structure according to claim 1, wherein said tiedown means comprises a plurality of relatively rigid tubular members having their upper ends connected to said housing at spaced locations thereon and lower ends anchored to the floor of the body of water in which said housing is immersed and wherein said tubular members are of such dimensions as to be essentially weightless in water and of neither negative nor positive buoyancy.
 11. In combination, a buoyant object and tiedown means for anchoring said buoyant object to the floor of a body of water; said tiedown means comprising a relatively rigid, hollow tubular member sealed to prevent water frOm entering the interior thereof and of such dimensions as to be relatively weightless in water and of neither negative nor positive buoyancy; said tubular tiedown member having an upper end connected to said buoyant object and a lower end adapted to be anchored to the floor of the body of water.
 12. An underwater structure, comprising: a housing adapted to be immersed in a body of water; means in the housing for exposing the interior thereof to the pressure of the water in which said housing is to be immersed; said housing being adapted to contain a fluid at least partially filling the interior thereof; said fluid being of lower specific gravity than the water in which said housing is to be immersed, and said fluid being of such pressure relative to the pressure of the water in which said housing is to be immersed as to prevent the water from rising above a predetermined level within the housing; and tiedown means connected to said housing and adapted to extend between said housing and the floor of the body of water in which said housing is to be immersed for anchoring the housing to the floor and maintaining the housing a predetermined distance above the floor.
 13. An underwater structure according to claim 12, and further comprising an access column having a lower end communicating with the interior of said housing and extending upwardly and terminating in an upper end spaced substantially above said housing, whereby said upper end of said access column will extend above the surface of a body of water when said housing is immersed in that body of water.
 14. An underwater structure according to claim 12, wherein said tiedown means comprises a relatively rigid tubular member having an upper end connected to said housing and a lower end adapted to be anchored to the floor of a body of water in which said housing is immersed and wherein said tubular tiedown member is a hollow tubular member sealed to prevent water from entering the interior thereof and of such dimensions as to be relatively weightless in water and of neither negative nor positive buoyancy. 